The present invention relates generally to adapters for use with packaged devices or other adapter apparatus (e.g., ball grid array (BGA) packages, land grid array or other surface mount devices, male pin adapters, female socket adapter apparatus, etc.).
Certain types of integrated circuit packages are becoming increasingly popular due to their occupancy area efficiency. In other words, they occupy less area on a target board on which they are mounted while providing a high density of contact terminals. For example, one such high density package type is a ball grid array package.
Generally, ball grid array packages contain an integrated circuit having its die bond pads electrically connected to respective conductive solder spheres that are distributed on the bottom surface of the package in an array. A target printed circuit board typically has formed on its surface a corresponding array of conductive pads which align with the array of solder spheres for electrically mounting the ball grid array package on the target board.
The target board typically includes other conductive traces and elements which lead from the array of conductive pads used for mounting the ball grid array package to other circuitry on the board for connecting various components mounted thereon. Typically, to mount such a ball grid array package to a target board, the package is positioned with the array of solder spheres corresponding to the array of conductive pads on the target board. The resulting structure is then heated until the solder spheres are melted and fused to the conductive pads of the target board.
Such area efficient packaging (e.g., ball grid array packages) provide a high density of terminals at a very low cost. Also, this packaging provides for limited lead lengths. Limited lead lengths may reduce the risk of damage to such leads of the package, may provide for higher speed product, etc.
Generally, circuit boards and/or components mounted thereon are tested by designers as the circuit boards are being developed. For example, for a designer to test a circuit board and/or a ball grid array package mounted thereon, the designer must first electrically connect the solder spheres on the ball grid array package to the target circuit board. As described above, this generally includes mounting the ball grid array package on the target board and heating the solder spheres to fuse the solder spheres to the conductive pads of the target board. Therefore, the package may be prevented from being used again. It is desirable for various reasons to use package adapters for mounting the packages and reuse ball grid array packages after testing. For example, such ball grid array packages may be relatively expensive. Further, for example, once attached, the solder spheres are not accessible for testing. In addition, it is often difficult to rework the circuit board with packages soldered thereon.
Various adapters which are used for electrically connecting the ball grid array package to a target printed circuit board are known. For example, U.S. Pat. No. 6,007,348 to Murphy, issued 28 Dec. 1999, entitled “Solder Sphere Terminal,” and U.S. Pat. No. 6,325,280 to Murphy, issued 4 Dec. 2001, entitled “Solder Sphere Terminal,” describe several adapter apparatus for use in mounting ball grid array packages. For example, as described therein, various intercoupling components are provided. In one of such components, an insulative support member includes a plurality of terminal elements positioned within holes extending through the insulative support member. The terminal elements are sized to be press-fit within the holes of the insulative support member.
The intercoupling components described in U.S. Pat. No. 6,007,348 and U.S. Pat. No. 6,325,280, as well as other conventional devices, in many instances have terminals (e.g., female socket pins) that are press-fit into openings formed in an insulative material configured for receiving a mating terminal (e.g., female socket pins configured to receive male pins). However, such press-fitting of terminals into openings of such insulative support materials present one or more varied problems.
For example, the press-fitting of pins in the insulative material cause stresses to the material that can cause the part when loaded with a plurality of pins to warp. Such warping may especially be evident when the adapter apparatus including the press-fit terminals is exposed to heat (e.g., such as during a reflow process).
Further, press-fitting of pins into openings of such an adapter apparatus can cause micro-fracturing of the insulative material when the holes are sized too tightly (e.g., with intolerable tolerances). Such micro-fracturing of the insulative materials undesirably allows for solder during further processing to flow to undesirable locations of the apparatus (e.g., the fractures of the insulative materials). Such solder flow may cause soldering to the target board to fail with loss of yield on an initial production run.
Yet further, in many circumstances, substrates which have terminals that are press-fit within openings defined therethrough (e.g., when press-fitting a female socket pin into openings of an adapter substrate) require the need for multiple hole sizes to be formed to permit the press-fit to effectively hold the terminal in place. The hole sizes in the substrate generally require tight control in dimension to make sure that solder does not migrate up or along the terminal (e.g., socket pin) during processing. Such a tightly controlled dimensional substrate is relatively expensive to manufacture. Still further, the use of press-fit terminals also yields problems due to the difficulty of controlling a drilling process for forming the openings, if drilling is used to form such openings in the adapter substrate.